Drive mechanism for agitator blades in a paste container

ABSTRACT

The invention relates to a paste container with a follower plate tightly sealing the open side of the container. A multiblade mixing propeller is fitted to the follower plate in such a way that it can be rotated, a short distance beneath the follower plate, around an axle ( 5 ) which juts through the middle of the plate. The paste container includes a removal device with an external drive mechanism with which paste can be removed from the container through an opening in the follower plate. The agitator blades and the removal device have the same drive mechanism. The paste container is used in particular for receiving thixotropic pastes.

BACKGROUND

1.0 Field of the Invention

This invention relates generally to paste containers, and moreparticularly to paste containers including dispensing mechanisms.

2.0 Discussion of Related Art

Paste-form detergents are growing in importance and are beingincreasingly used in laundries. Paste-form detergents have theadvantages of powder-form detergents, especially their highactive-ingredient contents, but none of the disadvantages of liquiddetergents, especially their water or solvent contents. Paste-formdetergents are often pseudoplastic or thixotropic pastes, moreparticularly high-viscosity detergent pastes, which are mainly used ininstitutional laundries.

Pseudoplastic or thixotropic pastes have the property whereby theirviscosity is reduced by mechanical shearing, for example by stirring orshaking or under the effect of ultrasound, but is restored after removalof the mechanical stress. This means that this property whereby theviscosity of such pastes decreases under the effect of increasing shearstress or shear rate can be utilized to make handling easier.Unfortunately, these properties of paste-form detergents, especiallyhigh-viscosity pastes, also cause particular packaging and handlingproblems.

German patent application P 43 32 850 describes a paste container with aremoval system which is suitable for accommodating and removing pastes.It consists of a cylinder open on one side and a tightly closingfollower plate arrangement for displacement on the open side of thecylinder, and comprises a removal system for removing and transportingthe paste. A geared motor is mounted on the follower plate, amultiple-blade propeller stirrer being arranged on the shaft of themotor which extends centrally through the follower plate. The propellerstirrer is positioned just below the follower plate, and is able to turnfreely in the paste, the viscosity of the thixotropic paste beingreduced under the shearing effect. The paste which thus becomes easy totransport is delivered by the propeller stirrer to a removal systemwhich transports the paste through an opening in the follower plate, andwhich comprises an external drive mechanism.

This solution has the disadvantage that it is very expensive. Theseparate drives for the propeller stirrer and the removal system areexpensive and, because of the space they require, are difficult toaccommodate above the paste container.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an improved pastecontainer with a removal system for reducing manufacturing and operatingcosts, and for providing compact packaging. In one embodiment of theinvention, this object is met by providing a paste container with apropeller stirrer and removal system that share the same drivemechanism.

The paste container according to the invention has the advantage thatthe use of the same drive for the propeller stirrer and removal systemleads to a distinct reduction in manufacturing and operating costs, andthe limited space above the paste container can be better and moreefficiently utilized through the elimination of a unit. Since, in orderto reduce the viscosity of, and to transport, the thixotropic paste, thepaste need only be stirred when it is also to be removed, theamalgamation of the drives of the propeller stirrer and the removalsystem is particularly advantageous.

This drive combination is particularly favorable in an embodiment inwhich the removal system comprises a rotation shaft of a feed elementarranged perpendicularly of the follower plate. This can be solvedparticularly advantageously by the use of a screw pump which transportsthe paste delivered by the propeller stirrer outwards.

Where the removal system is non-centrally arranged, the distance to theshaft of the propeller stirrer can readily be bridged by interengaginggearwheels or a belt drive. If the removal system is centrally arrangedon the follower plate, the propeller shaft or boss may be formed withparticular advantage by lengthening the shaft of the feed element on theaxis of rotation of the screw.

In one particular embodiment where the transported paste is delivered toan injector, the feed line is designed to be closed by a shutoffelement, for example a ball cock, whereby the flow of paste can bebriefly interrupted with particular advantage until a substantiallyconstant feed volume has been established.

BRIEF DESCRIPTION OF THE DRAWING

Various embodiments of the invention are described with reference to thedrawing, which shows a partial cut-away view of a side elevational viewof the subject paste container, and associated stirrer feed or dispensermechanism.

DETAILED DESCRIPTION OF THE INVENTION

The drawing shows a cylindrical paste container 1 which is tightlyclosed by a follower plate 2, the follower plate 2 forming a seal withthe inner wall of the paste container 1. A propeller stirrer 4 ismounted on a shaft formed by an extension of the axis of rotation of thescrew.

The feed element 6 comprises a central feed passage 7 in which a screwtransporting element 5 rotates. The drive shared by the propellerstirrer 4 and the feed screw 5 is the motor 8 which is slidingly fixedto and guided by a guide 11 via a holder. In this way, the combinationof the removal system 6 and the propeller stirrer 4, including thecommon drive 8, can be vertically moved when the follower plate 2follows the falling level of the thixotropic paste 12 as the latter isremoved. The vent screw 10 has to be opened if the follower plate 2 isto be withdrawn after emptying of the paste container 1.

The amount of paste removed by the removal system 6 is determined by therotational speed and by other influencing factors, such as the passagediameter, screw volume and pitch. If the removal system 6 isnon-centrally arranged, the particular rotational speeds can be adaptedto meet specific functional requirements through the design of thegearing between the shafts of the removal system 6 and the propellerstirrer 4. If the shaft of the propeller stirrer 4 is formed by anextension of the feed element shaft, the propeller stirrer 4 rotates atthe same speed as the removal system so that inter alia the viscosity ofthe thixotropic paste is determined in this manner. In this case, therotational speed of the propeller stirrer 4 should be adjusted with therequired paste consistency in mind. On this basis, the feed volume isdetermined as a function of the other influencing factors.

A feed line (not shown) to a metering injector (not shown) may bedisposed at the opening 9. The feed line to the injector can be brieflyclosed by a ball cock. Depending on the length of the metering lines,the injector has to overcome a certain counterpressure after opening ofand water valve before it develops full power. The effect of this can bethat water is briefly forced into the paste line and, with extremelyshort metering times when the pump is unable to build up its fullpressure, can enter the section between the ball cock and the pastepump. Here, the highly alkaline paste can harden in the event ofrelatively long stoppages of the metering system, resulting in blockageof the injector. Similarly, the ball cock enables the hoses to be rinsedin the closed state without any contact with the paste 12.

What is claimed is:
 1. A paste container comprising a follower platewhich tightly seals the open side of the container, and on which amultiple-blade propeller stirrer is arranged in such a way that it isable to rotate just below the follower plate about a shaft extendingcentrally therethrough, and a removal system with an external drive withwhich paste can be removed from the container through an opening in thefollower plate, wherein the propeller stirrer and the removal systemhave the same drive.
 2. A paste container as claimed in claim 1, whereinthe removal system comprises a feed element which rotates about an axisextending perpendicularly of the follower plate.
 3. A paste container asclaimed in claim 2, wherein the removal system is a screw pump whichtransports the paste delivered by the propeller stirrer outwards.
 4. Apaste container as claimed in claim 3, wherein the removal system iscentrally arranged, and the propeller shaft is formed by an extension ofthe axis of rotation of the screw.
 5. A paste container as claimed inclaim 3, wherein the removal system delivers the transported paste to aninjector, the feed line being designed to be closed by a closureelement.
 6. A paste container as claimed in claim 2, wherein the removalsystem is centrally arranged, and the propeller shaft is formed by anextension of the axis of rotation of the screw.
 7. A paste container asclaimed in claim 6, wherein the removal system delivers the transportedpaste to an injector, the feed line being designed to be closed by aclosure element.
 8. A paste container as claimed in claim 2, wherein theremoval system delivers the transported paste to an injector, the feedline being designed to be closed by a closure element.
 9. A pastecontainer as claimed in claim 1, wherein the removal system delivers thetransported paste to an injector, the feed line being designed to beclosed by a closure element.